1. Field of the Invention
The invention relates to a power transfer mechanism, and more particularly to a system of gears.
2. Description of the Related Art
Multi-axial transfer of movement and rotational speed changes are normally achieved by using a gear train, such as one-to-one direct gear train, or one-to-many direct gear train.
In one-to-one direct gear train, assuming no frictional losses, energy transferred from the driving gear to a driven gear is equal to the energy generated by the driving gear. In one-to-more direct gear train, such as one-to-two direct gear train or one-to-three direct gear train, assuming no frictional losses, energy generated by the driving gear will be averagely transferred to each driven gear; that is, in one-to-two direct gear train, the energy transferred from the driving gear to each driven gear is about half of the energy generated by the driving gear, and in one-to-three direct gear train, energy transferred from the driving gear to each driven gear is about third of the energy generated by the driving gear.
In a conventional gear train, the tooth pitch of the driving gear is equal to the tooth pitch of the driven gear, that is, one tooth of the driving gear corresponds to and is engaged with one tooth of each driven gear. Referring to FIG. 2, a conventional gear train comprises a driving gear 5 and a driven gear 4 which are engaged with each other. The driving gear 5 is turned counterclockwise by an external force, and the driven gear 4 is turned clockwise by the driving gear 5. Therefore, energy is transferred from the driving gear 5 to the driven gear 4.
As shown in FIG. 2, in a conventional meshing gear train one tooth of the driving gear 5 corresponds to and is engaged with one tooth of the driven gear 4, and the number of teeth in the driving gear 5 is equal to the number of teeth in the driven gear 4. This is to say that the tooth pitch of the driving gear 5 defines the tooth pitch of the driven gear 4 and vice versa. However, this is often not the optimal solution for reducing manufacturing and operating costs of gear trains.